<DataSource ID="PortalRow" Constructor="PortalRow">
    <fields>
       	<field name="height"    type="measure"         title="Height"     xmlAttribute="true" basic="true" /> 
        <field name="minHeight" type="positiveInteger" title="Min Height" xmlAttribute="true"/>	
        <field name="maxHeight" type="positiveInteger" title="Max Height" xmlAttribute="true"/>	
        
        <!-- Note that type is "Canvas" because we will automatically generate the portlet if needed -->
        <field name="portlets" type="Canvas" multiple="true" />
    </fields>
</DataSource>
